SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d9b1b00422afbe2ec13960c0d86e0fe96a79fed593dcdff0e1eabbfbe85502f' 
  AND token = 'CdYcEj2BwGKZLmEW9dJnI4S6k8ruXpgYdQd8dC+Ozfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}